This invention relates to a novel construction for a micro relay. The invention will be described in the context of an array of micro relays. One application of such a device is in the controllable connection between a plurality of telephone subscriber lines and a plurality of lines to an exchange.
Such connections are typically executed using labor intensive, manually fitted wire pair jumpers typically located at at least two points between the exchange and the customer. The first jumpering point is the main distribution frame (MDF) typically located in the same building as the exchange. The second jumpering point is typically located in an outdoor cabinet or pillar near the customers. In some cases further jumpering may occur near the customer, eg. in sealed underground canisters located in small pits. The invention is suitable for application at any of these points.
The jumpers are used to connect or disconnect customer services as required, while maintaining efficient use of the cable pairs between the customers and the exchange, i.e., only using the valuable exchange pairs for active services.
In the case of the use of digital loop concentrators (DLC, an outdoor cabinet remote multiplexer) the MDF function is replaced by a cross connect field typically located within the DLC.
Relays are still used extensively in the telecommunication industry, for example, in telephone exchanges for line testing and application of ring voltage. Usually, these devices have been discrete devices, not manufactured in large arrays, and assembled from discrete components.
In the past, the main means of altering remote jumper connections was by physically changing the copper connections at a cabinet/pillar to which several customer copper connections were connected. This required a service person to travel from a depot to the location of the cabinet/pillar, identify the connections to be changed, and physically make the change before returning to the depot. This sequence of events is referred to colloquially as a truck-roll.
The advent of services such as ADSL creates an increased need for the ability to rapidly and efficiently change the customer connections.
In order to provide remotely controllable links between groups of lines, typically large matrices of relays are required. Conventional relays are not cost or space effective in this application. The present invention offers a means of fabricating large arrays of relays in compact form and with very low cost.
This invention proposes a micro relay device including a magnetic path formed of a movable armature at least partly of magnetizable material the magnetic path including magnetizable material carried by a support member, the support member including one or more through holes to permit the magnetic path to pass from a first side of the support member to a second side, the armature being proximate to the first side, the magnetic path extending along or proximate to the second side. Preferably the support member is in the form of a planar substrate.
The activation coil or coils for the relay are installed on or in the support member, and pass through a loop of the magnetic path.
The movable armature may be a cantilever, a meander, a spiral spring, or other suitable resilient structure. One embodiment includes a flexible membrane carrying a magnetic component and electrical contacts.
In a preferred embodiment, the invention provides a remotely switchable relay array to change subscriber connections.